1. Field of the Invention
The present disclosure relates to an electric motor.
2. Description of the Related Art
A spoke type IPM (Interior Permanent Magnet) motor has been known in the past, wherein magnets, of which a cross-sectional surface perpendicular to the center axis of the motor is rectangular, are radially disposed within the rotor core. In the spoke type motor, the surface on the longer side is magnetized, and the circumferentially adjacent magnets are arranged so that identical poles face each other. Also in the spoke type motor, in order to maintain the magnets in the rotor core, insert molding can be performed to provide resin around them.
For example, in the rotor core 23 of the motor 1 disclosed in Japanese Patent Application Publication No. 2010-63285, a magnet 25 is received in a slot 24. The entire magnet 25 is covered by a sealing resin 27. Accordingly, the magnet 25 and the rotor core 23 are integrally combined. The inner circumference of the rotor core 23 is not covered by the sealing resin 27.
The rotor 32 of the motor 1 disclosed in the second preferred embodiment of Japanese Patent Application Publication No. 2014-36457 has a laminated core 51, a plurality of magnets 52 and a resin portion 53. The laminated core 51, both axial end surfaces of the plurality of magnets 52 and radially outer surfaces of the magnets 52 are covered with the resin portion 53. The laminated core 51 has an inner core portion 61, a plurality of outer core portions 62 and a plurality of connecting portions 63. The plurality of connecting portions 63 connect the inner core portion 61 and the plurality of outer core portions 62. The top surface of an upper resin portion 531 of the resin portion 53 has a gate hole 91. The gate hole 91 is formed on the upper portion of the outer core portion 62. A lower resin portion 532 has a plurality of second positioning holes 94 disposed in an area which axially overlaps with an outer edge portion of the plurality of outer core portions 62. The resin portion 53 does not exist on the inner circumferential surface of the inner core portion.